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Help with these two maths trig questions please?

I'll link an attachment below and I'll explain what I've done so far :smile:

For the 1st 2 marker question I understand the opposite angle is 73 degrees because it's isocles and that's all I've gotten.
However on question 2 I've wrote so far...
(not sure if its correct)
all angles are 60 degrees in the triangles and the sides are 10. So I should half the rectangle into a right angled triangle and the side would be 20 cm and the angle 90 degrees and use tan?
but that's where im stuck :frown:
please explain and offer me guidance :smile:
(edited 9 years ago)
Untitled.jpg48.8KB
Original post by AlphaNick
1)
You're correct so far, ∠ACN (assume N is the midpoint of length X) is equal to 73°
You should then realise that it is possible to work out length x with the trigonometry equations:



Since you have the hypotenuse and the angle, and you're trying to work out the adjacent side, you should use the second equation listed.

Rearrange it to get:
(the dot means times by)

So do cos(73)*9

Then remember to double it to find the total length of x.


2)
Yeah, all angles in that upper triangle are 60°
90-60=30
So you should now have an angle of 30° and a side of 19cm, use the third equation I listed previously to work it out.




thanks for your help :smile:
is 1) = 5.2 cm correct
and 2) = 22 cm correct??
Reply 2
Avatar for Earth1
Earth1
9
Original post by AlphaNick
1 should be 5.26, so it would round to 5.3 at 2sf, be careful there but it looks fine.

2 I got 32.9 cm, check again

I agree :smile:

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